id like to build a atleast a 1500hp motor
- Thread starter MASTER6
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billet crank, billet rods, arp everything. id recommend an alum block so that it will be a true 4 bolt main. I have a boss block and was making 988 rwhp and the main caps were starting to walk. the caps were digging into the block. I have pics if you care to see. my car made about 1200 fwhp with a 329ci stroker with a single 76mm precision dual ball bearing billet wheel turbo.
Wow really...I've never heard of anyone having main caps walk on a Boss block. Definitely doesn't make me feel comfortable, can you post the pics?
I'll go out to the garage later and take some pics
This. I just ordered a boss block as well. I was told the alum block wouldn't hold the power.
here is one of the main caps on the block side
and here is the main cap itself. it was moving. I also had arp main studs and the side caps were arp also....
this motor had dyno time and about 150-200 street miles only!
its a 3.800 kellog 4340 crank
5.315 manley billet I-beam rods
arp everything
boss block
and here is the main cap itself. it was moving. I also had arp main studs and the side caps were arp also....
this motor had dyno time and about 150-200 street miles only!
its a 3.800 kellog 4340 crank
5.315 manley billet I-beam rods
arp everything
boss block
There are stock ford aluminum blocks making 1000-2500hp all over the place
this is true. honestly the alum block with the TRUE 4-bolt mains and sleeved block is probably stronger than the boss block.
im pissed that I wasted money on the boss block honestly.
If I am not mistaken, the stock aluminum block that holds insane power is the Teksid version. The Ford version is only good for like 800? The Teksid block came in some of the earlier Cobras and Mark VIII's. The webbing down the center of the Teksid blocks in square, it is diamonds on the Ford block. I think something is reversed on the Mark VIII block though? I don't remember, so do some research if you try to find one.
What sealing issues?? News to me
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Head gasket sealing issues! Mihovetz has tested the Boss block and found out about the main cap issue as well as the head gasket issue..
NOW I do remember reading that you can drill into the main caps to make them a 4bolt main. .It takes machines and some custom work but that ford designed the main caps to have that done if need be.
This is why I got rid of my Boss block and went with a Teksid block std bore. I had it deburred for extra strength, ARP 2000 bolts everywhere as well
NOW I do remember reading that you can drill into the main caps to make them a 4bolt main. .It takes machines and some custom work but that ford designed the main caps to have that done if need be.
This is why I got rid of my Boss block and went with a Teksid block std bore. I had it deburred for extra strength, ARP 2000 bolts everywhere as well
Well shit that explains my head gasket leak also.Head gasket sealing issues! Mihovetz has tested the Boss block and found out about the main cap issue as well as the head gasket issue..
NOW I do remember reading that you can drill into the main caps to make them a 4bolt main. .It takes machines and some custom work but that ford designed the main caps to have that done if need be.
This is why I got rid of my Boss block and went with a Teksid block std bore. I had it deburred for extra strength, ARP 2000 bolts everywhere as well
What a load of shit ford. Now I'm mad
Makes me want to get a class action lawsuit started. I've spent a butt load of money on my car and to have problems like this is unacceptable.
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Yea it's sad but true. We found all this out after I had built my last motor which sucks.. Like I said you can drill the other part of the main caps for a 4 bolt main which will help with the cap walk.. There is also rumors that the head gasket issue can be fixed if you tq down the head studs to like 120ftlbs vise 90 or something taking care of that issue. You have to use the ARP 2000 pro series head studs though, which are bank.
Here's the article about drilling the main caps
http://www.mustangandfords.com/how-to/engine/m5lp-0803-frpp-mustang-block/
Here's the article about drilling the main caps
http://www.mustangandfords.com/how-to/engine/m5lp-0803-frpp-mustang-block/
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well for now im gonna keep my parts. I got a stock long block and im going to slap my turbo on it. I cant afford to "chance" this motor with maybe fixes.
.........and stressing the engine to 1200 hp had nothing to do with it!
I get a bit leery when someone makes blanket statements like this when there is usually more to the story and at that power level there is. Did you honestly think you were building an engine that would be reliable? You are pushing the structural integrity of the engine to it's limits. That damage occurred when the engine was strapped down and tortured on that dyno. This motor was on "borrowed time" before it got it's first sip of fuel it took the 200 miles of street driving before the problem manifested itself. Bottom end failures are very rare in these engines this is the first time I've seen a main cap on an iron block walk like that 9 times out of 10 the pistons are what fails. Something tells me had this been a Teksid block under the same circumstances the results would have been the same. A 1200 hp mod motor is nothing more than a ticking time bomb!
Mod motor aluminum blocks uses 4 main cap bolts because it needs them due to the fact their being held in by soft aluminum threads which can't be torqued down like the caps bolts in an iron block (imagine if it only had 2 it would fail in a heartbeat :uh oh
. The bolts directly adjacent to the crank journals are what takes-up the majority of the stress. If that bolt is sunk into aluminum threads you would want to add a second set to compensate for the loss of strength. Adding a second set of main bearing caps on an iron block would remove material weakening the cap which would negate some of the benefit of having 4 bolts. The cross bolt design is light years ahead of a conventional 4 bolt cap anyhow. Having one walk like yours did is a bit surprising due to how well the caps are registered but at that power level all bets are off! For a street car at a more modest power level the boss block for sheer durability will be hard to beat. If you look at the main bearing saddles, the side bolt arrangement, Siamesed cylinders you realize it is basically an iron version of the teksid. At 16 psi on gasoline I expect my "stock stroke" Boss block to get many many miles on it before rebuild time and when I do chances are all it will need is for the cylinders to get cleaned-up and that may or may not require going to the next oversize (I'm on my 3rd set of stock bore pistons on a 2 stroke road racer with 3 overbore left on the jugs :rolling
.Next time I would dial back the HP and break the engine in gently. I think in the long run you will be much happier that way :burnout:
.........and stressing the engine to 1200 hp had nothing to do with it!
I get a bit leery when someone makes blanket statements like this when there is usually more to the story and at that power level there is. Did you honestly think you were building an engine that would be reliable? You are pushing the structural integrity of the engine to it's limits. That damage occurred when the engine was strapped down and tortured on that dyno. This motor was on "borrowed time" before it got it's first sip of fuel it took the 200 miles of street driving before the problem manifested itself. Bottom end failures are very rare in these engines this is the first time I've seen a main cap on an iron block walk like that 9 times out of 10 the pistons are what fails. Something tells me had this been a Teksid block under the same circumstances the results would have been the same. A 1200 hp mod motor is nothing more than a ticking time bomb!
Mod motor aluminum blocks uses 4 main cap bolts because it needs them due to the fact their being held in by soft aluminum threads which can't be torqued down like the caps bolts in an iron block (imagine if it only had 2 it would fail in a heartbeat :uh oh
For a street car at a more modest power level the boss block for sheer durability will be hard to beat. If you look at the main bearing saddles, the side bolt arrangement, Siamesed cylinders you realize it is basically an iron version of the teksid. At 16 psi on gasoline I expect my "stock stroke" Boss block to get many many miles on it before rebuild time and when I do chances are all it will need is for the cylinders to get cleaned-up and that may or may not require going to the next oversize (I'm on my 3rd set of stock bore pistons on a 2 stroke road racer with 3 overbore left on the jugs :rolling
Next time I would dial back the HP and break the engine in gently. I think in the long run you will be much happier that way :burnout:
It made almost 800rwhp on 15.8 psi
This car had several issues but I don't blame the tuner. I've had an engine shop at road Atlanta look at it that specializes in hp and extreme running conditions.
I should also mention that it twisted the crank and it will have to be reground.
This block perhaps just can't take the abuse and as others have stated. It has head sealing issues and main cap walk issues noted from a well known engine builder.
I'm not sure what I'm gonna do with my other engine but for now I got a stock one and I'm gonna take my time with it.
Also there are a good number of 1000+ hp mod motors out here not failing and they are also not using the boss block either....makes you go hummmm
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The way that I see it is like this.. John Mihovetz, has the fastest 281c.i engine on the planet.. He runs a Teksid block.. Granted I'm sure it's modified in some ways.. But if it's good enough for 2500hp it's good enough for my near 800rwhp I'll be pushing, and again my Tekisid has been deburred, and has better dowels in them as well. If J.M believed the Boss block was good at holding that much power he would be using it..
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